New vs used solar panels

[Dinky greg]

I am looking at buying solar panels to set up a small home based solar power plant. Last night while browsing the Internet to find out online stores to buy solar panels. I stumbled across some ads on classified regarding selling of used solar panels. Cost of these used solar panels is much less than buying new ones. So I am interested in buying used solar panels, but I read somewhere that buying used solar panels can be a bad deal. I don't want to compromise on efficiency and quality. Can anyone point me in the right direction and help me on this topic?

Thanks..

[Rob Beckers]

Hi Greg,

Welcome at Green Power Talk!
The way to test them (if you can), is on a sunny day, measure the output voltage and compare with the specifications. It's listed there as "Voc", for "open circuit". The voltage changes with temperature of the cells, and is normally listed at 25C (it goes up when colder, less voltage when warmer). Deviations may indicate bad cells. Next is the short-circuit current. To measure this flip the panel over so the cells are facing down (and not getting any light), then either short-circuit the two leads coming and use a DC rated clamp meter, or insert the wires in a multi-meter set for current. Flip panel so it faces the sun and see what you get. The short circuit current is listed in the specs as "Isc". Those to values should give you a good idea of the state of the module.

Besides the electrical, look for water intrusion, and the state of the sealant. Decent modules should last for 30+ years, so used ones can well be a good value. But unless they are exceedingly cheap I would not buy them without measuring their electrical parameters first.

-RoB-

[Paul Bailey]

Welcome Greg:
If the panel still appears good, and as Rob stated above ,tests Ok ,and the price is right your good to go. New panels of all Brands have dropped Alot in price in the last 2 years,so be careful here. Here are a couple Pics in the news lately of a 30 year old Arco panel taken down off this guys roof and tested petty much as new as it looks. Degradation is usually in the .270 % Per /Year range . If you want more on the story I try to find the Link for you to read it. Every Panel will probably test with a differant result , dont expect them all to be the same if one is good. Heres some pics of the Arco test,... and a 2 year old ( Brand Name panels) in need of a big time Warranty claim Ouch!!! Paul:worried:

[Dale Sheler]

Welcome Greg:
If the panel still appears good, and as Rob stated above ,tests Ok ,and the price is right your good to go. New panels of all Brands have dropped Alot in price in the last 2 years,so be careful here. Here are a couple Pics in the news lately of a 30 year old Arco panel taken down off this guys roof and tested petty much as new as it looks. Degradation is usually in the .270 % Per /Year range . If you want more on the story I try to find the Link for you to read it. Every Panel will probably test with a differant result , dont expect them all to be the same if one is good. Heres some pics of the Arco test,... and a 2 year old ( Brand Name panels) in need of a big time Warranty claim Ouch!!! Paul:worried:

What is that in those panels? Condensation?

[Roxie Covelli]

Hello greg!

I believe we're on the same boat. I also want to know if buying used solar panels would be okay since they're relatively cheaper than new ones. But one thing for sure, I'm scared that I could spend for nothing. What if it doesn't work that well anymore? But I did learn that it is actually quite convenient to buy used ones, although we just have to be careful and make sure that they're still working well. But you can't expect them to work as great as the new one's, though it could still depend of how old the panel was used. :)

I could not add anymore to what the others' suggested. I think they made such good points and I couldn't agree more. ;)